notify alternative to auto gc?

Hi,

As I did a git pull on my project today, git went into some kind of auto gc mode:

Auto packing the repository for optimum performance. You may also run "git gc" manually. See "git help gc" for more information. Counting objects: 4531, done.

This is, of course, quite an annoying feature since it could hit at any (inconvenient) time.

The git help tells me I can disable it by setting gc.auto to 0, while the mailing list archive tells me I also have to set gc.autopacklimit to 0.  This is fine, but if I do that, I won't know when the repo is in need of cleanup.  Is there any option I can set to instruct it to simply TELL me when it's in need of gc?